Pump apparatus with switching valve and driving power transmission device

ABSTRACT

A pump apparatus with a switching valve includes an actuator that is rotationally driven, a pump, a switching valve and a driving power interrupting device. The pump discharges a fluid sucked by rotational driving of the actuator. The switching valve is changed in phase by the rotational driving of the actuator so as to be switchable among a plurality of destinations of the fluid discharged from a pump chamber of the pump. The driving power interrupting device for a valve is switchable between a state where rotational driving power of the actuator is transmitted to the switching valve and a state where the rotational driving power of the actuator is interrupted.

BACKGROUND

The present invention relates to a pump apparatus with a switching valvethat includes a switching valve that is switchable among a plurality ofdestinations of a fluid and discharges a sucked fluid to a switcheddestination.

For example, in a drive device for an automobile described in PatentDocument 1, a hydraulic control device that controls a supply ofhydraulic pressure from a pump via a plurality of magnetic valves to aplurality of hydraulic cylinders, respectively, and performs connectionand disconnection of a plurality of wet multiple disc clutches,respectively, is described.

Additionally, the present invention relates to a driving powertransmission device that transmits driving power between two shaftmembers.

For example, in a driving power transmission device for an automobile(driving power distribution device) described in Patent Document 2, adriving power transmission device including an auxiliary transmissionthat shifts the power from an input shaft and transmits the power to amain output shaft, and a friction clutch that transmits a torque fromthe main output shaft to an auxiliary output shaft is described.

-   [Patent Document 1] JP-A-2009-269605-   [Patent Document 2] JP-A-2008-114674

SUMMARY

In the hydraulic control device described in the above Patent Document1, complicated drive control is required because a plurality ofactuators that drive the pump and the plurality of magnetic valves,respectively, are provided. Additionally, costs tend to increase becausethe number of devices is large.

Additionally, in the driving power transmission device described in theabove Patent Document 2, in the case of a locking mode where an engagedstate of the friction clutch is maintained, it is necessary to continuesupplying a high current to a motor that actuates the friction clutch.For this reason, fuel consumption tends to increase for power storage.

The invention has been made in view of such a situation, and an objectthereof is to provide a pump apparatus with a switching valve that canperform rotational driving of a pump and rotational driving of aswitching valve with one actuator, respectively.

Additionally, another object of the invention is to provide a drivingpower transmission device that can suppress current consumption.

According to one advantageous aspect of the present invention, there isprovided a pump apparatus with a switching valve comprising:

an actuator that is rotationally driven;

a pump that discharges a fluid sucked by rotational driving of theactuator;

a switching valve that is changed in phase by the rotational driving ofthe actuator so as to be switchable among a plurality of destinations ofthe fluid discharged from a pump chamber of the pump; and

a driving power interrupting device for a valve that is switchablebetween a state where rotational driving power of the actuator istransmitted to the switching valve and a state where the rotationaldriving power of the actuator is interrupted.

Accordingly, the rotational driving of the pump and the rotationaldriving of the switching valve can be performed by one actuator byperforming switching using the driving power interrupting device for avalve. Thus, the drive control of one actuator becomes simple, and thehigh-speed operation of the pump apparatus with a switching valve ispossible.

Additionally, since the number of devices can be reduced, remarkablecost reduction can be achieved.

The driving power interrupting device for a valve may transmit therotational driving power of the actuator in one rotational direction tothe switching valve and may interrupt the rotational driving power ofthe actuator in the other rotational direction with respect to theswitching valve.

Accordingly, the switching valve can be reliably rotationally driven androtationally stopped.

The actuator may rotationally drive the pump with the rotational drivingpower of the actuator in one rotational direction, and the driving powerinterrupting device for a valve may transmit the rotational drivingpower of the actuator in the other rotational direction to the switchingvalve.

Accordingly, the pump and the switching valve can be reliably switchedand rotationally driven.

The driving power interrupting device for a valve may be a one-wayclutch that transmits the rotational driving power of the actuator inthe other rotational direction to the switching valve and interrupts therotational driving power of the actuator in one rotational direction,and the pump apparatus with a switching valve may include a drivingpower interrupting device for a pump that is a one-way clutch andtransmits the rotational driving power of the actuator in one rotationaldirection to the pump and interrupts the rotational driving power of theactuator in the other rotational direction.

Accordingly, the fluid can be reliably supplied to a predetermineddestination without simultaneously actuating the rotational driving ofthe pump and the rotational driving of the switching valve.

The pump apparatus with a switching valve may include a housing thatrotatably houses the switching valve, the switching valve may have abraking device that is switchable between a state where the rotationthereof with respect to the housing is constrained and a state where therotation thereof with respect to the housing is released, the brakingdevice may release the switching valve when the actuator is rotationallydriven in one rotational direction, and the braking device may constrainthe switching valve when the actuator is rotationally driven in theother rotational direction.

Accordingly, the rotational phase detection and positioning of theswitching valve can be reliably performed, and the switching of theswitching valve can be reliably performed.

A rotational axis of the actuator, a rotational axis of the pump, and arotational axis of the switching valve may be coaxially provided, an endsurface of the switching valve may form a side wall of a pump chamber ofthe pump, and the pump apparatus with a switching valve may include ahousing that houses the pump and the switching valve.

Accordingly, the pump apparatus with a switching valve can be downsized.

At least one of the switching valve and a surface of the housing facingthe switching valve may be provided with a circumferential groove intowhich a fluid discharged from the pump chamber is made to flow, and thehousing may be provided with a communication hole that communicates apressure detecting mechanism with the circumferential groove.

Accordingly, the pressure of each of the plurality of destinations ofthe fluid can be detected by one pressure detecting mechanism.

The pump apparatus with a switching valve may include a side plate thatforms a side wall of the pump chamber opposite to the switching valve,the pump may have an outer rotor and an inner rotor and may include acam ring that eccentrically and rotatably supports the outer rotor withrespect to the inner rotor, and the switching valve, the side plate, andthe cam ring may rotate integrally.

Accordingly, the pump and the switching valve can be integrated side byside in the direction of the rotational axis, and the pump apparatuswith a switching valve can be further downsized.

The side plate may be housed in the housing.

A back-pressure chamber, into which the fluid discharged from the pumpchamber flows, and applying a pressing force to the pump side to theside plate with the pressure of the fluid, may be provided between anend surface of the side plate opposite to the pump chamber in adirection of a rotational axis and the housing facing the end surface ofthe side plate in the direction of the rotational axis.

Since the fluid has a high pressure during the operation of the pump,there is a concern that the fluid may leak if a gap is formed betweenthe pump and the side plate or between the pump and the housing.However, the positional relationship between the side plate and thehousing can be maintained by the pressing force generated by theback-pressure chamber, and the leaking of the fluid from the above gapcan be prevented.

The pump apparatus with a switching valve may include a thrust bearingarranged at the housing so as to sandwich the pump, the switching valve,and the side plate in the direction of the rotational axis.

Since there is no pumping action when the switching valve isrotationally driven, it is difficult to integrally rotate the sideplate, the pump, and the switching valve. However, since the thrustbearing is provided, the side plate, the pump, and the switching valvecan be integrally and smoothly rotated without rattling.

The switching valve may be changed in phase so as to be switchable amonga plurality of return points made to communicate with a suction side ofthe pump chamber of the pump.

Accordingly, the fluid can be smoothly returned and reused.

The pump apparatus with a switching valve may include a control devicethat controls rotational driving of the actuator on the basis of thepressure of the fluid detected by the pressure detecting mechanism.

Accordingly, the driving of the actuator can be exactly controlled sothat the pressure of the fluid becomes proper.

The pump apparatus with a switching valve may include a phase detectingmechanism capable of detecting and positioning the phase.

Accordingly, a plurality of destinations of the fluid discharged fromthe pump chamber can be reliably switched.

The pump apparatus with a switching valve may include a control devicethat controls rotational driving of the actuator on the basis of thephase of the switching valve detected by the phase detecting mechanism.

Accordingly, the driving of the actuator can be exactly controlled sothat the destination of the fluid becomes accurate.

The phase detecting mechanism may be constituted of a sensor that isfixed to the housing that rotatably houses the rotary valve and isprovided to make the amount of protrusion from an inner peripheralsurface of the housing to a radial inner side variable, and a recessthat that is formed in an outer peripheral surface of the switchingvalve and is locked to the sensor in a circumferential direction.

Since a high pressure is applied to the switching valve during theoperation of the pump, there is a concern that the switching valve mayidle only with the driving power interrupting device for a valve.However, since the recess to be locked in the circumferential directionto the sensor is provided, the idling of the switching valve can beprevented.

The pump is a rotary pump that makes the pressure of the sucked fluidhigh through the rotational driving of the actuator to discharge thehigh-pressure fluid, and the pump apparatus with a switching valve ofthe invention further includes a speed change gear that makes areduction ratio when the rotational driving power of the actuator istransmitted to the rotary pump greater than a reduction ratio when therotational driving power of the actuator is transmitted to the switchingvalve.

Accordingly, the reduction ratio when the rotational driving power ofthe actuator is transmitted to the rotary pump is greater than thereduction ratio when the rotational driving power is transmitted to theswitching valve. Thus, the rotational driving of the rotary pump and theswitching valve can be performed, respectively, by one actuator. Hence,the pump apparatus with a switching valve can be simply controlled, andan improvement in pump efficiency and an improvement in valvepositioning accuracy can be made compatible.

The speed change gear may be a reduction gear coupled to the switchingvalve, and the rotary pump may be directly connected to the actuator.

Accordingly, since the speed change gear can be simply configured, costreduction of the pump apparatus with a switching valve can be achieved.

The speed change gear may include a first reduction gear coupled to theswitching valve and a second reduction gear coupled to the rotary pump.Accordingly, the pumping pressure of the rotary pump can be increased.

A rotational axis of the actuator, a rotational axis of the rotary pump,a rotational axis of the switching valve, and a rotational axis of thespeed change gear may be coaxially provided, an end surface of theswitching valve may form a side wall of the pump chamber, and the pumpapparatus with a switching valve may include a housing that houses therotary pump, the switching valve, and the speed change gear.

Accordingly, the pump apparatus with a switching valve can be downsized.

The pump apparatus with a switching valve may include a side plate thatforms a side wall of the pump chamber opposite to the switching valve,the rotary pump may have an outer rotor and an inner rotor and include acam ring that eccentrically and rotatably supports the outer rotor withrespect to the inner rotor, and the switching valve, the side plate, thecam ring, and the speed change gear rotate integrally.

Accordingly, the rotary pump and the switching valve can be integratedside by side in the direction of the rotational axis, and the pumpapparatus with a switching valve can be further downsized.

The pump apparatus with a switching valve may include a thrust bearingarranged at the housing so as to sandwich the rotary pump, the switchingvalve, the side plate, and the speed change gear in the direction of therotational axis.

Since there is no pumping action when the switching valve isrotationally driven, it is difficult to integrally rotate the sideplate, the rotary pump, and the switching valve. However, since thethrust bearing is provided, the side plate, the rotary pump, and theswitching valve can be integrally and smoothly rotated without rattling.

According to another advantageous aspect of the present invention, thereis provided a driving power transmission device comprising:

a fluid pressure type clutch device that transmits driving power betweentwo shaft members; and

a pump apparatus that supplies a fluid to the clutch device

wherein the pump apparatus includes:

a pump that makes a pressure of sucked fluid high to discharge the fluidwith a high-pressure;

a first flow passage through which the fluid according to a pressuredischarged from the pump is supplied to the clutch device during adriving of the pump;

a second flow passage through which the fluid discharged from the pumpis held during the stop of the pump and a pressing force is applied tothe clutch device by the fluid to be held; and

a switching valve that is switchable between a normal mode where adischarge port of the pump is made to communicate with the first flowpassage and a locking mode where the discharge port of the pump is madeto communicate with the second flow passage.

Accordingly, the normal mode and the locking mode are switched by theswitching valve. Thus, the pressure of the fluid can be maintained evenif the driving of the pump apparatus is stopped in the locking mode.Accordingly, the current consumption of the driving power transmissiondevice can be suppressed.

The second flow passage may be provided with a check valve thatregulates a back flow of the fluid to the pump side during the stop ofthe pump and permits the supply of the fluid to the clutch device sideduring the driving of the pump.

Accordingly, the leak of the fluid can be suppressed in the lockingmode, and the pressure of the fluid can be maintained for a prolongedperiod of time.

The driving power transmission device may include a pressureaccumulation device that accumulates the fluid when the pressure of thefluid within the second flow passage is equal to or higher than apredetermined pressure and that discharges the accumulated fluid to thesecond flow passage during the stop of the pump when the pressure of thefluid within the second flow passage is reduced.

Accordingly, the pressure of the fluid can be maintained for a prolongedperiod of time. Hence, the driving of the pump apparatus can be stoppedfor a long time, and the current consumption of the driving powertransmission device can be further suppressed.

The driving power transmission device may include an actuator that isrotationally driven, and the switching valve may be a rotary valve thatis changed in phase by the rotational driving of the actuator so as tobe switchable between the normal mode and the locking mode.

Accordingly, the normal mode and the locking mode can be easily andreliably switched.

The pump may be a rotary pump that includes an outer rotor and an innerrotor that form a pump chamber in a radially facing region and makes thepressure of sucked fluid high through the rotational driving of theactuator to discharge the high-pressure fluid. A rotational axis of theactuator, a rotational axis of the pump, and a rotational axis of therotary valve may be coaxially provided, and an end surface of the rotaryvalve may form a side wall of the pump chamber.

Accordingly, the rotary pump and the rotary valve can be integrated sideby side in the direction of the rotational axis, and the driving powertransmission device can be further downsized.

The first flow passage may be provided with a drain port thatcommunicates with the pump suction side when the switching valve is inthe normal mode, and a flow control valve may be provided so as to beswitchable between a state where the fluid is supplied from the pump tothe clutch device side by closing the drain port when the switchingvalve is in the normal mode and the pump is driven and a state where thefluid is discharged from the first flow passage to the suction side ofthe pump by opening the drain port when the switching valve is in thenormal mode and the pump is stopped.

Accordingly, the pressure of the fluid can be rapidly lowered from theswitching place, and the driving power transmission device can beactuated at a high speed.

The flow control valve may be biased to the switching valve side by abiasing member, the flow control valve may be provided with a throttlethat makes the pressure of the fluid of the flow control valve on theclutch device side greater than the pressure of the fluid of the flowcontrol valve on the switching valve side in a state where the fluid issupplied, and the flow control valve may be moved to a position wherethe drain port is closed against a biasing force of the biasing member,by a pressure difference of the fluid.

Accordingly, the fluid can be smoothly supplied to the switching placeand the driving power transmission device can be actuated at a higherspeed.

The clutch device may be applied to a differential gear with limiteddifferential that distributes the driving power of a driving source to adrive shaft on a front wheel side and a drive shaft on a rear wheel sideand limits the differential between the drive shaft on the front wheelside and the drive shaft on the rear wheel side, and the clutch devicemay limit the differential between the drive shaft on the front wheelside and the drive shaft on the rear wheel side according to anengagement force.

Accordingly, a center differential function of a vehicle can beenhanced.

The clutch device may be provided between a drive shaft on a front wheelside and a drive shaft on a rear wheel side and may distribute thedriving power of a driving source to the front wheel side and the rearwheel side according to an engagement force.

Accordingly, a coupling function of the vehicle can be enhanced.

The clutch device may be applied to a differential gear with limiteddifferential that distributes the driving power of a driving source to adrive shaft on a left wheel side and a drive shaft on a right wheel sideand limits the differential between the drive shaft on the left wheelside and the drive shaft on the right wheel side, and the clutch devicemay limit the differential between the drive shaft on the left wheelside and the drive shaft on the right wheel side according to anengagement force.

Accordingly, front differential and rear differential functions of thevehicle can be enhanced.

The driving power transmission device may include an input shaft thatreceives driving power input from a driving source; and an auxiliarytransmission that includes a cylinder device driven according to a fluidpressure difference between two partitioned regions, changes a speedchange ratio of the driving power input to the input shaft, according tothe position of a piston of the cylinder device, and transmits thechanged driving power to a wheel, the pump apparatus may include thirdand fourth flow passages that communicate with the respective regions ofthe cylinder device, and the switching valve may be switchable among thenormal mode, the locking mode, and an auxiliary transmission switchingmode where the cylinder device is driven by making a discharge port anda suction port of the pump communicate within the third and fourth flowpassages, respectively.

Accordingly, a function of the auxiliary transmission of the vehicle canbe increased.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1A is a view illustrating a schematic configuration of a drivesystem of a vehicle on which a pump apparatus with a switching valverelated to an embodiment is mounted.

FIG. 1B is a view illustrating a schematic configuration of a drivesystem of another vehicle on which the pump apparatus with a switchingvalve related to the embodiment is mounted.

FIG. 2 is a cross-sectional view illustrating a schematic structure ofan auxiliary transmission.

FIG. 3 is a cross-sectional view illustrating a detailed structure of acenter LSD of a driving power transmission device.

FIG. 4 is a view illustrating a schematic configuration of the drivingpower transmission device constituted of the center LSD, the pumpapparatus with a switching valve that operates a clutch device of thecenter LSD, and the auxiliary transmission.

FIG. 5 is a view illustrating an axial cross-section of the pumpapparatus with a switching valve.

FIG. 6 is a view illustrating a rotary pump and a first pump housing ofthe pump apparatus with a switching valve as viewed from an arrow A ofFIG. 5.

FIG. 7 is a view illustrating a rotary valve, a speed change gear, and asecond pump housing of the pump apparatus with a switching valve asviewed from an arrow B of FIG. 5.

FIG. 8 is a view illustrating only the rotary valve of FIG. 7.

FIG. 9 is a view illustrating only the second pump housing of FIG. 7.

FIG. 10 is a view illustrating only the speed change gear of FIG. 7.

FIG. 11A is a view illustrating the state of a flow passage in a normalmode of the pump apparatus with a switching valve.

FIG. 11B is a view illustrating the state of a flow control valve whenhydraulic oil is supplied in the normal mode of the pump apparatus witha switching valve.

FIG. 11C is a view illustrating the state of the flow control valve whenhydraulic oil is discharged in the normal mode of the pump apparatuswith a switching valve.

FIG. 12A is a view illustrating the state of the flow passage in alocking mode of the pump apparatus with a switching valve.

FIG. 12B is a view illustrating the states of a check valve, anaccumulator, and a cylinder device when hydraulic oil is supplied in thelocking mode of the pump apparatus with a switching valve.

FIG. 12C is a view illustrating the states of the check valve, theaccumulator, and the cylinder device when supply of the hydraulic oil isstopped in the locking mode of the pump apparatus with a switchingvalve.

FIG. 13A is a view illustrating the states of the flow passage and thecylinder device in an auxiliary transmission switching mode (Lo) of thepump apparatus with a switching valve.

FIG. 13B is a view illustrating the states of the flow passage and thecylinder device in an auxiliary transmission switching mode (Hi) of thepump apparatus with a switching valve.

DETAILED DESCRIPTION OF EXEMPLIFIED EMBODIMENTS

(Outline of Vehicle)

Hereinafter, an embodiment of a pump apparatus with a switching valve(driving power transmission device) of the invention will be describedreferring to the drawings. First, schematic configurations of drivesystems of vehicles 1 and 8 on which a pump apparatus 100 with aswitching valve of the present embodiment is mounted will be describedwith reference to FIGS. 1A and 1B. In addition, in FIG. 1B, the samecomponents as those of FIG. 1A will be designated by the same referencenumerals, and the detailed description thereof will be omitted.

As illustrated in FIG. 1A, the vehicle 1 is a four-wheel drive car, andis configured to include an engine 2 (equivalent to a driving source ofthe invention), a transmission 3, an auxiliary transmission 4, apropeller shaft 5F on front wheels Wfl and Wfr side, a propeller shaft5R on rear wheels Wrl and Wrr side, a drive shaft 6FL on a front leftwheel Wfl side, a drive shaft 6FR on a front right wheel Wfr side, adrive shaft 6RL on a rear left wheel Wrl side, a drive shaft 6RR on arear right wheel Wrr side, a front limited slip differential (LSD) 7F, acenter LSD 7C, a rear LSD 7R, and three pump apparatuses 100 with aswitching valve. The respective shafts 5F, 5R, 6FL, 6FR, 6RL, and 6RRare equivalent to a “drive shaft” of the invention.

Each of the LSDs 7F, 7C, and 7R includes a hydraulic clutch device 7(refer to FIG. 4) that has a multiple disc clutch 72 and a hydrauliccylinder device 73 for driving power transmission.

The front LSD 7F is a differential gear with limited differential thatdistributes the driving power of the engine 2 to the drive shaft 6FL onthe front left wheel Wfl side and the drive shaft 6FR on the front rightwheel Wfr side and that limits the differential between the drive shaft6FL on the front left wheel Wfl side and the drive shaft 6FR on thefront right wheel Wfr side according to the engagement force of theclutch device 7.

The center LSD 7C is a differential gear with limited differential thatoperates similarly to the front LSD 7F, on the propeller shaft 5F on thefront wheels Wfl and Wfr side and the propeller shaft 5R on the rearwheels Wrl and Wrr side.

The rear LSD 7R is a differential gear with limited differential thatoperates similarly to the front LSD 7F, on the drive shaft 6RL on therear left wheel Wrl side and the drive shaft 6RR on the rear right wheelWrr side.

The auxiliary transmission 4 includes a hydraulic cylinder device 41(refer to FIG. 4) that is driven according to a fluid pressuredifference between two partitioned regions 41 a and 41 b. The cylinderdevice 41 of the auxiliary transmission 4 is operated by the pumpapparatus 100 with a switching valve that operates the clutch device 7of the center LSD 7C.

Here, the schematic structure of the auxiliary transmission 4 will bedescribed with reference to FIG. 2. The auxiliary transmission 4includes a planetary gear mechanism consisting of a sun gear 43, aplanetary gear 44, a planetary carrier 45, and a ring gear 46. The sungear 43 is formed on one end side of an input shaft 31 from thetransmission 3. The ring gear 46 is fixed to an inner wall of a housing47 of the auxiliary transmission 4. The input shaft 31 and an outputshaft 21 are coaxially arranged and are configured so as to be able tobe spline-coupled via a coupling member 48. Additionally, the planetarycarrier 45 and the output shaft 21 are also configured so as to be ableto be spline-coupled via the coupling member 48. Then, the couplingmember 48 is engaged with a shift fork 49 coupled to a piston 42 of thecylinder device 41.

For example, as illustrated above a one-dot chain line of FIG. 2, whenthe piston 42 of the cylinder device 41 is located on a region 41 aside, the input shaft 31 and the output shaft 21 are coupled via thecoupling member 48. Thus, a speed change ratio of driving power input tothe input shaft 31 is 1/1, and is in a Hi mode where the driving poweris output to the output shaft 21 without deceleration. Additionally, asillustrated below the one-dot chain line of FIG. 2, when the piston 42of the cylinder device 41 is located on a region 41 b side, theplanetary carrier 45 and the output shaft 21 are coupled via thecoupling member 48. Thus, the speed change ratio of the driving powerinput to the input shaft 31 is in a Lo mode where the driving power isreduced in a reduction ratio according to the numbers of teeth of thesun gear 43, the planetary gear 44, and the ring gear 46 and is outputto the output shaft. Also, switching is made from the Hi mode to the Lomode by moving the position of the piston 42 from the region 41 b sideto the region 41 a side and switching is made from the Lo mode to the Himode by moving the position of the piston 42 from the region 41 a sideto the region 41 b side.

A driving power transmission device is constituted of the front LSD 7Fand the pump apparatus 100 with a switching valve that operates theclutch device 7 of the front LSD 7F. The same also applies for the rearLSD 7R. A driving power transmission device is constituted of the centerLSD 7C, the auxiliary transmission 4, the pump apparatus 100 with aswitching valve, and the input shaft 31 from the transmission 3.

In the vehicle 1, the driving power from the engine 2 or the like istransmitted to the center LSD 7C via the transmission 3 and theauxiliary transmission 4. Then, the center LSD 7C distributes thetransmitted driving power to the propeller shafts 5F and 5R.Additionally, the differential of the propeller shafts 5F and 5R islimited according to the engagement force of the multiple disc clutch 72of the clutch device 7 that is operated by hydraulic oil (equivalent toa “fluid” of the invention) supplied from the pump apparatus 100 with aswitching valve.

The driving power distributed to propeller shafts 5F and 5R istransmitted to the front LSD 7F and the rear LSD 7R. The front LSD 7Fdistributes the transmitted driving power to the drive shafts 6FL and6FR according to the same operation as the center LSD 7C. The rear LSD7R distributes the transmitted driving power to the drive shafts 6RL and6RR according to the same operation as the center LSD 7C.

The vehicle 8 illustrated in FIG. 1B is configured to include ahydraulic coupling device 9 instead of the center LSD 7C of the vehicle1 illustrated in FIG. 1A. The coupling device 9 includes the clutchdevice 7 that has the multiple disc clutch 72 and the cylinder device 73for driving power transmission. Also, the driving power transmissiondevice is constituted of the coupling device 9 and the pump apparatus100 with a switching valve that operates the clutch device 7 of thecoupling device 9.

The coupling device 9 is a device that is provided between the propellershaft 5F on the front wheels Wfl and Wfr side and the propeller shaft 5Ron the rear wheels Wrl and Wrr side and distributes driving power to thepropeller shaft 5F on the front wheels Wfl and Wfr side, and thepropeller shaft 5R on the rear wheels Wrl and Wrr side according to theengagement force of the clutch device 7.

Here, the detailed structure of the center LSD 7C will be described asan example with reference to FIG. 3. As illustrated in FIG. 3, thecenter LSD 7C is configured to include a planetary gear mechanism 71,the multiple disc clutch 72, the cylinder device 73, the housing 74, andthe like.

The planetary gear mechanism 71 includes a sun gear 71 a, a planetarygear 71 b, a carrier 71 c, and an internal gear 71 d. The multiple discclutch 72 includes an inner plate 72 a and an outer plate 72 b. Thecylinder device 73 includes a cylinder 73 a, a piston 73 b, and a rod 73c.

The propeller shaft 5F on the front wheels Wfl and Wfr side is fitted tothe center of the sun gear 71 a. Additionally, the sun gear 71 a isformed with a cylindrical portion 71 as extending in the direction of arotational axis. Also, a plurality of the inner plates 72 a are fixed toan outer periphery of the cylindrical portion 71 as at predeterminedintervals.

The carrier 71 c is integrated with an end surface 74 a of the housing74 on the propeller shaft 5F side. An end surface 74 b of the housing 74opposite to the end surface 74 a on the propeller shaft 5F side isformed with a cylindrical portion 74 bb extending in the direction ofthe rotational axis. Also, the output shaft 21 from the auxiliarytransmission 4 is fitted to an inner periphery of the cylindricalportion 74 bb.

The internal gear 71 d is formed with a cylindrical portion 71 dd thatcovers the multiple disc clutch 72, goes around an inner peripheral sideof the sun gear 71 a, and has a U-shaped cross-section. Also, aplurality of the outer plates 72 b are fixed to the inner periphery ofthe cylindrical portion 71 dd facing the outer periphery of thecylindrical portion 71 as of the sun gear 71 a so as to be arrangedalternately with the inner plates 72 a. Additionally, a shaft (in FIG.3, denoted by 5R for convenience) coupled to the propeller shaft 5R onthe rear wheels Wrl and Wrr side via a gear mechanism is fitted to theinner periphery of the cylindrical portion 71 dd facing the innerperiphery of the cylindrical portion 71 aa of the sun gear 71 a. Theshaft 5R is inserted through a hollow inner peripheral portion of thepropeller shaft 5F.

The cylinder 73 a and the piston 73 b are arranged parallel to eachother on the outer side, in the direction of the rotational axis, of theend surface 74 a of the housing 74 on the propeller shaft 5R side. Also,the rod 73 c is arranged within the planetary gear 71 b so as to pressthe inner plates 72 a and the outer plates 72 b in an engageable manner.

(Schematic Configuration of Driving Power Transmission Device)

Next, the driving power transmission device constituted of the centerLSD 7C, the pump apparatus 100 with a switching valve that operates theclutch device 7 of the center LSD 7C and the auxiliary transmission 4will be described with reference to FIG. 4.

As illustrated in FIG. 4, the pump apparatus 100 with a switching valveis configured to include an actuator 110, a rotary pump 120 (equivalentto a “pump” of the invention), a rotary valve 130 (equivalent to a“switching valve” of the invention), a speed change gear 140, a drivingpower interrupting device 150 for a valve, a driving power interruptingdevice 151 for a pump, a phase detecting mechanism 160, a pressuredetecting mechanism 170, a check valve 180, an accumulator 190, acontrol device 200, first to fourth flow passages P1 to P4, an oilsuction and discharge passage P5, and the like. In addition, machinecomponents of the pump apparatus 100 with a switching valve will bedescribed below in detail.

The cylinder device 73 of the clutch device 7 of the center LSD 7C ispipe-connected to the pump apparatus 100 with a switching valve throughthe first flow passage P1 and the second flow passage P2. In addition,the first flow passage P1 and the second flow passage P2 are integratedwith each other in the middle of the piping. The cylinder device 41 ofthe auxiliary transmission 4 is pipe-connected to the pump apparatus 100with a switching valve through the third flow passage P3 and the fourthflow passage P4. Additionally, the pump apparatus 100 with a switchingvalve is pipe-connected to a reservoir tank T through the oil suctionand discharge passage P5.

The first flow passage P1 is, in a normal mode to be described below, aflow passage for supplying the hydraulic oil according to a pressuredischarged from the rotary pump 120, to the cylinder device 73 of theclutch device 7, during the rotational driving of the rotary pump 120and for returning the hydraulic oil within the cylinder device 73 to thepump apparatus 100 with a switching valve during the stop of therotational driving of the rotary pump 120.

The second flow passage P2 is, in a locking mode to be described below,a flow passage for holding the hydraulic oil discharged from the rotarypump 120 during the rotational driving of the rotary pump 120 and forapplying a pressing force to the cylinder device 73 of the clutch device7 with the held hydraulic oil during the stop of the rotational drivingof the rotary pump 120.

The third flow passage P3 is, in an auxiliary transmission switchingmode to be described below, a flow passage for supplying the hydraulicoil discharged from the rotary pump 120 to the region 41 a of thecylinder device 41 of the auxiliary transmission 4 and for returning thehydraulic oil pushed out from the region 41 a of the cylinder device 41to the pump apparatus 100 with a switching valve when the hydraulic oilis supplied to the region 41 b of the cylinder device 41.

The fourth flow passage P4 is, in the auxiliary transmission switchingmode, a flow passage for supplying the hydraulic oil discharged from therotary pump 120 to the region 41 b of the cylinder device 41 of theauxiliary transmission 4 and for returning the hydraulic oil pushed outfrom the region 41 b of the cylinder device 41 to the pump apparatus 100with a switching valve when the hydraulic oil is supplied to the region41 a of the cylinder device 41.

The oil suction and discharge passage P5 is a flow passage for returningthe hydraulic oil returned from the cylinder device 73 of the clutchdevice 7 or the cylinder device 41 of the auxiliary transmission 4 tothe reservoir tank T.

(Machine Components of Pump Apparatus with Switching Valve)

The machine components of the pump apparatus 100 with a switching valvewill be described with reference to the drawings. As illustrated in FIG.5, the pump apparatus 100 with a switching valve is constituted of asmall device in which the machine components, such as theabove-described actuator 110, are housed side by side in the directionof the rotational axis in a motor housing Hm, a first pump housing Hp1,and a second pump housing Hp2, which are integrated and have a hollowbox shape.

That is, the actuator 110 is housed in the motor housing Hm having ahollow box shape. The rotary pump 120, the rotary valve 130, the speedchange gear 140, and the like are housed within a space formed bycombining the first pump housing Hp1 and the second pump housing Hp2.

As illustrated in FIG. 5, the actuator 110 is a motor that isrotationally driven, and includes a stator 111, a rotor 112, a rotaryshaft 113, and the like.

The stator 111 is constituted of a coil or the like and is fixed to aninner periphery of the motor housing Hm. The rotor 112 is formed in theshape of a basket and has a permanent magnet 112 a arranged at an outerperiphery thereof, and an end portion of the rotary shaft 113 is fittedto the center of the basket so that the rotary shaft 113 protrudes fromthe inside of the basket.

The rotor 112 is arranged on an inner peripheral side of the stator 111so as to be rotatable around an outer peripheral side of the cylindricalportion Hp1a provided to protrude in the direction of the rotationalaxis from a central portion of the first pump housing Hp1. That is, anouter periphery of a portion 113 a of the rotary shaft 113 within thebasket is rotatably supported on an inner periphery of the cylindricalportion Hp1a via a radial bearing 114.

As illustrated in FIGS. 5 and 6, the rotary pump 120 is a pump thatdischarges sucked hydraulic oil through the rotational driving of theactuator 110 so as to have high pressure, and includes a cam ring 121,an outer rotor 122, an inner rotor 123, and the like.

The cam ring 121 is formed in the shape of a flat ring in which an innerperiphery of the cam ring is made eccentric with respect to an outerperiphery thereof.

The outer rotor 122 is formed in the shape of a ring having almost thesame external diameter and thickness as the internal diameter andthickness of the cam ring 121 and having internal teeth 122 a, and isrotatably arranged at an inner periphery of the cam ring 121. Theinternal teeth 122 a are constituted of a plurality of trochoid curves.

The inner rotor 123 is formed in the shape of a ring having almost thesame thickness as the thickness of the outer rotor 122 and havingexternal teeth 123 a engageable with the internal teeth 122 a, and isrotatably arranged at an inner periphery of the outer rotor 122. Theexternal teeth 123 a are constituted of a plurality of trochoid curvesthat are fewer than the number of teeth of the internal teeth 122 a. Therotary shaft 113 of the actuator 110 is integrally rotatably fitted tothe center of the inner rotor 123 via the driving power interruptingdevice 151 for a pump.

The rotary pump 120 is sandwiched by a side plate 125 that is rotatablyinserted into a bottomed tubular space Hp1b recessed at a centralportion of the first pump housing Hp1, and a rotary valve 130 that isrotatably inserted into a bottomed tubular space Hp2b recessed at acentral portion of the second pump housing Hp2. Accordingly, the outerrotor 122 and the inner rotor 123 form a pump chamber 124 in a radiallyfacing region, and a plate end surface 125 c and a valve end surface 130c of the side plate 125 and the rotary valve 130 in the direction of therotational axis on the pump chamber 124 side form both side walls of thepump chamber 124.

A step portion 125 dd is formed on an outer peripheral side of a plateend surface 125 d of the side plate 125 in the direction of therotational axis on a side opposite to the pump chamber. A back-pressurechamber 125 e for causing the hydraulic oil discharged from the pumpchamber 124 to flow thereinto and for applying a pressing force to therotary pump 120 side to the side plate 125 with the pressure of thehydraulic oil is provided between the step portion 125 dd and the firstpump housing Hp1 facing the step portion 125 dd.

Since the fluid has a high pressure during the operation of the rotarypump 120, there is a concern that the fluid may leak if a gap is formedbetween the rotary pump 120 and the side plate 125, between the rotarypump 120 and the motor housing Hm, and between first pump housing Hp1and the second pump housing Hp2. However, the positional relationshipbetween the side plate 125 and the motor housing Hm, the first pumphousing Hp1, and the second pump housing Hp2 can be maintained by thepressing force generated by the back-pressure chamber 125 e, and theleaking of the fluid from the above gap can be prevented.

The side plate 125, the cam ring 121 of the rotary pump 120, and therotary valve 130 are coupled together by a pin 127. A seal ring 125 g isfitted between the plate end surface 125 d and a plate peripheralsurface 125 f of the side plate 125 and the first pump housing Hp1.Also, a pair of thrust bearings 126 are arranged at the first and secondpump housing Hp1 and Hp2 so as to sandwich the side plate 125, therotary pump 120, and the rotary valve 130 in the direction of therotational axis from both sides. Accordingly, the side plate 125, therotary pump 120, and the rotary valve 130 become integrally and smoothlyrotatable without rattling.

Crescent suction-side grooves 125 a and 130 a and crescentdischarge-side grooves 125 b and 130 b are formed so as to berespectively recessed at predetermined intervals along a circumferentialdirection of both the end surfaces 125 c and 130 c of the pump chamber124, in both the end surfaces 125 c and 130 c of the pump chamber 124 inthe side plate 125 and the rotary valve 130. Positions where thesuction-side grooves 125 a and 130 a and the discharge-side grooves 125b and 130 b are formed are located on a track along which a space formedbetween the external teeth 123 a and the internal teeth 122 a moves.

The rotary valve 130 is formed with a suction flow passage 131 thatcommunicates with the pump chamber 124 from a bottom portion of thesuction-side groove 130 a (refer to FIGS. 5, 7, and 8). A position wherethe suction flow passage 131 communicates with the bottom portion of thesuction-side groove 130 a is a starting end of the suction-side groove130 a where the space formed between the external teeth 123 a and theinternal teeth 122 a first passes through the suction-side groove 130 a.Additionally, the rotary valve 130 is formed with a discharge flowpassage 132 that communicates with the pump chamber 124 from a bottomportion of the discharge-side groove 130 b (refer to FIGS. 5, 7, and 8).A position where the discharge flow passage 132 communicates with thebottom portion of the discharge-side groove 130 b is an intermediateportion of the discharge-side groove 130 b.

In the rotary pump 120, if the actuator 110 is rotationally driven, theinner rotor 123 rotates in the counterclockwise direction of FIG. 6, andthe outer rotor 122 meshing with the external teeth 123 a through theinternal teeth 122 a also rotates in the counterclockwise direction ofFIG. 6. Then, since the space formed between the external teeth 123 aand the internal teeth 122 a moves from the suction-side groove 130 a tothe discharge-side groove 130 b and the pressure on the discharge sideof the pump chamber 124 becomes higher than the pressure on the suctionside of the pump chamber 124, the hydraulic oil is fed from the suctionflow passage 131 to the discharge flow passage 132.

The rotary valve 130 is a switching valve that is changed in phase bythe rotational driving of the actuator 110 so as to be switchable amonga plurality of destinations of the hydraulic oil discharged from thepump chamber 124 and switchable among a plurality of return points madeto communicate with the suction side of the pump chamber 124.Accordingly, the fluid can be smoothly returned and reused.

The rotary valve 130 is a switching valve that is switchable among thenormal mode where the discharge side of the pump chamber 124 is made tocommunicate with a first flow passage P1, the locking mode where thedischarge side of the pump chamber 124 is made to communicate with thesecond flow passage P2, and the auxiliary transmission switching modewhere the cylinder device 41 is driven by making the discharge side andthe suction side of the pump chamber 124 communicate with the third andfourth flow passages P3 and P4, respectively.

As illustrated in FIGS. 5, 7, and 8, a hole 130 g through which acylindrical portion 141 a of the sun gear 141 of the speed change gear140 extending in the direction of the rotational axis is insertable witha gap is drilled at the center of the rotary valve 130.

The above-described suction flow passage 131 and discharge flow passage132 are formed inside the rotary valve 130. Here, a path of the suctionflow passage 131 and the discharge flow passage 132 when the opening 131a within the suction-side groove 130 a of the suction flow passage 131and the opening 132 a within the discharge-side groove 130 b of thedischarge flow passage 132 are located in a left-right directionillustrated in FIG. 8 will be described.

The suction flow passage 131 is a path which extends from the opening131 a within the suction-side groove 130 a to a position with almosthalf the thickness of the rotary valve 130 toward the valve end surface130 d on the opposite side in the direction of the rotational axis,which is bent perpendicularly diagonally in a downward leftwarddirection at that position and extends to and opens at a valve outerperiphery, and which is bent and branched in the direction of therotational axis before reaching the valve outer periphery 130 e andextends to and opens at the valve end surface 130 d. The branched flowpassage is a flow passage 131 c for drain for discharging the hydraulicoil to the reservoir tank T.

That is, the hydraulic oil within the reservoir tank T enters the rotaryvalve 130 from an opening 131 d of the valve outer periphery 130 ethrough the oil suction and discharge passage P5, and is sucked from theopening 131 a through the suction flow passage 131 to the pump chamber124. Additionally, the hydraulic oil from the cylinder device 73 passesthrough the suction flow passage 131 extending from the flow passage 131c for drain to the valve outer periphery 130 e through the first flowpassage P1, and is discharged from the opening 131 d of the valve outerperiphery 130 e through the oil suction and discharge passage P5 to thereservoir tank T.

The discharge flow passage 132 is a path which extends from the opening132 a within the discharge-side groove 130 b to the position with almosthalf the thickness of the rotary valve 130 toward the valve end surface130 d on the opposite side in the direction of the rotational axis,which is bent perpendicularly diagonally in an upward leftward directionat that position and is bent in the direction of the rotational axisbefore reaching the valve outer periphery 130 e, and which extends toand opens at the valve end surface 130 d. That is, an opening 131 b ofthe valve end surface 130 d of the flow passage 131 c for drain and anopening 132 b of the valve end surface 130 d of the discharge flowpassage 132 are drilled at positions (positions separated by 180 degreesfrom each other in the circumferential direction) that arepoint-symmetrical to each other with respect to the center of the rotaryvalve 130.

The valve end surface 130 d of the rotary valve 130 is provided with acircumferential groove 133 that allows the hydraulic oil discharged fromthe pump chamber 124 to flow thereinto. The circumferential groove 133is provided in order to detect the pressure of each of a plurality ofdestinations of the hydraulic oil discharged from the pump chamber 124,using the pressure detecting mechanism 170 communicating therewith. Forthis reason, the circumferential groove 133 communicates with a flowpassage 132 c for pressure detection branched from the middle of thedischarge flow passage 132.

A seal ring 134 is fitted outside and inside the circumferential groove133 in order to prevent the leaking of the hydraulic oil from thecircumferential groove 133. By forming such an annular groove, thepressure of each of all the destinations can be detected by one pressuredetecting mechanism 170 even if the rotary valve 130 rotates. Inaddition, as the pressure detecting mechanism 170, there is a pressuredetecting sensor using electric capacity, strain, or the like.

Moreover, four protrusions 135 that are inserted into respective gaps offour planetary gears 142 of the speed change gear 140 and rotatecoaxially with the speed change gear 140 are provided so as to protrudeat equal angular intervals from the valve end surface 130 d of therotary valve 130.

Recesses 161 that constitute the phase detecting mechanism 160 and havea wedge-shaped radial cross-section are provided at intervals of 45degrees at the valve outer periphery 130 e of the rotary valve 130. Therecesses 161 are provided in order to detect and position the rotationalphase of the rotary valve 130, in cooperation with the phase detectingsensor 162 that constitutes the phase detecting mechanism 160. Namely,the recesses 161 and the phase detecting sensor 162 function as abraking device that is switchable between a state where the rotation ofthe rotary valve 130 with respect to the first housing Hp1 is restrainedfor the rotational phase detection and positioning of the rotary valve130 and a state where the rotary valve 130 is released with respect tothe first housing Hp1 for the switching of the flow passage 131 or thelike of the rotary valve 130.

By inserting the phase detecting sensor 162 into such a triangularcolumnar recess, the phase detecting sensor 162 abuts against the wallof a recess 161 when the rotary valve 130 tends to rotate in thecounterclockwise direction of the drawing. Thus, counterclockwiserotation can be prevented, and the rotational phase of the rotary valve130 can be detected and positioned. Accordingly, a plurality ofdestinations of the fluid discharged from the pump chamber 124 can bereliably switched.

As illustrated in FIGS. 5, 7, and 9, the second pump housing Hp2 isprovided with a communication suction flow passage 136 capable ofcommunicating with the suction flow passage 131 provided in the rotaryvalve 130, and is provided with a flow passage 136 c for communicationdrain, a first suction and discharge flow passage 139 a, and a secondsuction and discharge flow passage 139 b capable of communicating withthe flow passage 131 c for drain. Additionally, a normal discharge flowpassage 137 and a locking discharge flow passage 138 capable ofcommunicating with the discharge flow passage 132 is provided. Inaddition, the first suction and discharge flow passage 139 a and thesecond suction and discharge flow passage 139 b are also capable ofcommunicating with the discharge flow passage 132. Moreover, a flowpassage 137 c (equivalent to a “communication hole” of the invention)for communication pressure detection that always communicates with theflow passage 132 c for pressure detection is provided.

An opening 136 a of the communication suction flow passage 136 thatcoincides with the opening 131 d of the valve outer periphery 130 e ofthe suction flow passage 131 when a rotary valve 130 is rotated andpositioned in a predetermined phase is provided in an inner periphery ofa space Hp2b of the second pump housing Hp2. Moreover, a bottom portionof the space Hp2b of the second pump housing Hp2 is provided with anopening 136 d of the flow passage 136 c for communication drain thatcoincides with the opening 131 b of the valve end surface 130 d of theflow passage 131 c for drain and an opening 137 a of the communicationdischarge flow passage 137 that coincides with the opening 132 b of thevalve end surface 130 d of the discharge flow passage 132, when theabove phase positioning is performed.

Namely, the positional relationship between the opening 136 d of theflow passage 136 c for communication drain and the opening 137 a of thenormal discharge flow passage 137 is the same as the positionalrelationship between the opening 131 b of the flow passage 131 c fordrain and the opening 132 b of the discharge flow passage 132, and theseopenings are drilled at upper and lower positions separated by 180degrees from each other in the circumferential direction in the bottomportion of the space Hp2b. When the openings 136 d and 131 b coincidewith each other and the openings 137 a and 132 b coincide with eachother, the phase detecting sensor 162 is inserted into a predeterminedrecess 161 to detect and position a rotational phase.

Moreover, the bottom portion of the space Hp2b of the second pumphousing Hp2 is provided with an opening 139 c of the first suction anddischarge flow passage 139 a and an opening 139 d of the second suctionand discharge flow passage 139 b that coincide with the opening 131 b ofthe valve end surface 130 d of the flow passage 131 c for drain and theopening 132 b of the valve end surface 130 d of the discharge flowpassage 132, when the rotary valve 130 has been rotated by 90 degrees inthe clockwise direction or in the counterclockwise direction of thedrawing from a state where the openings 136 d and 131 b coincide witheach other and the openings 137 a and 132 b coincide with each other.

Namely, the positional relationship between the opening 139 c of thefirst suction and discharge flow passage 139 a and the opening 139 d ofthe second suction and discharge flow passage 139 b is the same as thepositional relationship between the opening 131 b of the flow passage131 c for drain and the opening 132 b of the discharge flow passage 132,and these openings are drilled in left and right positions (positionsshifted by 90 degrees in the circumferential direction with respect tothe positional relationship between the opening 136 d for communicationdrain of the flow passage 136 c and the opening 137 a of the normaldischarge flow passage 137) separated by 180 degrees from each other inthe circumferential direction in the bottom portion of the space Hp2b.When the openings 139 c and 131 b coincide with each other and theopenings 139 d and 132 b coincide with each other, the phase detectingsensor 162 is inserted into a recess 161 to detect and position arotational phase.

Moreover, the bottom portion of the space Hp2b of second pump housingHp2 is provided with an opening 138 a of the locking discharge flowpassage 138 that coincides with the opening 132 b of the valve endsurface 130 d of the discharge flow passage 132 when the rotary valve130 has been rotated by 45 degrees in the counterclockwise direction ofthe drawing from a state where the openings 136 d and 131 b coincidewith each other and the openings 137 a and 132 b coincide with eachother. In this case, the opening 136 d of the flow passage 136 c forcommunication drain and the opening 137 a of the normal discharge flowpassage 137 are closed with a lid 130 f provided in the valve endsurface 130 d.

Additionally, the bottom portion of the space Hp2b of the second pumphousing Hp2 is provided with an opening 137 d of the flow passage 137 cfor communication pressure detection that always coincides with thecircumferential groove 133 of the rotary valve 130.

Next, a path of the communication suction flow passage 136, the flowpassage 136 c for communication drain, the normal discharge flow passage137, the locking discharge flow passage 138, the first suction anddischarge flow passage 139 a, the second suction and discharge flowpassage 139 b, and the flow passage 137 c for communication pressuredetection will be described.

The communication suction flow passage 136 is a path that extends andopens at a bottom surface of the second pump housing Hp2 radiallydownward from the opening 136 a of the inner periphery of the space Hp2bof the second pump housing Hp2.

The flow passage 136 c for communication drain is a path which extendsfrom the opening 136 d of the bottom portion of the space Hp2b of thesecond pump housing Hp2 to the position with almost half the thicknessof the second pump housing Hp2 toward a housing end surface opposite toa housing end surface in which the space Hp2b is provided in thedirection of the rotational axis, which is bent perpendicularlyrightward at that position and bent perpendicularly upward beforereaching a housing side surface, and which communicates with a valvehole 137 b provided in the normal discharge flow passage 137. A portthat communicates with the valve hole 137 b of the flow passage 136 cfor communication drain is a drain port 136 e.

The normal discharge flow passage 137 is a path which extends from theopening 137 a of the bottom portion of the space Hp2b of the second pumphousing Hp2 to the position with almost half the thickness of the secondpump housing Hp2 toward the housing end surface opposite to the housingend surface in which the space Hp2b is provided in the direction of therotational axis, and which leads to the valve hole 137 b bentperpendicularly rightward at that position and formed at the housingside surface. The valve hole 137 b includes a flow control valve 152connected to the first flow passage P1.

The flow control valve 152 is provided with a throttle 152 a that makesthe pressure of the hydraulic oil on the clutch device 7 side (firstflow passage P1 side) of the flow control valve 152 greater than thepressure of the hydraulic oil on the rotary valve 130 side (the normaldischarge flow passage 137 side) in a state where the hydraulic oil issupplied.

The flow control valve 152 is biased to the normal discharge flowpassage 137 side by the restoring force of a compression spring 152 b(equivalent to a “biasing member” of the invention) within the valvehole 137 b when the rotary valve 130 is in the normal mode and therotary pump 120 is stopped. Additionally, the flow control valve 152 ismoved to a position where the drain port 136 e is closed against therestoring force of the compression spring 152 b, by the pressuredifference of the hydraulic oil when the rotary valve 130 is in thenormal mode and the rotary pump 120 is driven.

That is, the flow control valve 152 is a valve that is switchablebetween a state where the hydraulic oil is supplied from the dischargeside of the rotary pump 120 to the clutch device 7 side by closing thedrain port 136 e and a state where the hydraulic oil is discharged fromthe clutch device 7 side to the suction side of the rotary pump 120 byopening the drain port 136 e. Accordingly, the fluid can be smoothlysupplied to a switching place, the pressure of the fluid can be rapidlylowered from the switching place, and the driving power transmissiondevice can be actuated at a high speed.

The locking discharge flow passage 138 is a path which extends from theopening 138 a of the bottom portion of the space Hp2b of the second pumphousing Hp2 to the position with almost half the thickness of the secondpump housing Hp2 toward the housing end surface opposite to the housingend surface in which the space Hp2b is provided in the direction of therotational axis, which is bent perpendicularly upward, and which leadsto a check valve 180 connected to the second flow passage P2 provided ina housing upper surface.

The check valve 180 is a valve that always presses a valve body 181against a discharge port of the locking discharge flow passage 138through the action of a compression spring 182, regulates a back flow ofthe hydraulic oil to the rotary pump 120 side during the stop of therotary pump 120, and permits the supply of the hydraulic oil to theclutch device 7 side during the driving of the rotary pump 120.Accordingly, the leaking of the fluid can be suppressed in the lockingmode, and the pressure of the fluid can be maintained for a prolongedperiod of time.

The first suction and discharge flow passage 139 a and the secondsuction and discharge flow passage 139 b are a path that extends to andopens at the housing end surface opposite to the housing end surface inwhich the space Hp2b is provided in the direction of the rotational axisfrom the openings 139 c and 139 d of the bottom portion of the spaceHp2b of the second pump housing Hp2.

The flow passage 137 c for communication pressure detection is a pathwhich extends from the opening 137 d of the bottom portion of the spaceHp2b of the second pump housing Hp2 to the position with almost half thethickness of the second pump housing Hp2 toward the housing end surfaceopposite to the housing end surface in which the space Hp2b is providedin the direction of the rotational axis, and which is bentperpendicularly leftward at that position and extends to and opens atthe housing side surface.

As illustrated in FIGS. 5, 7, and 10, the speed change gear 140 is areduction gear that makes a reduction ratio when the rotational drivingpower of the actuator 110 is transmitted to the rotary pump 120 greaterthan the reduction ratio when the rotational driving power istransmitted to the rotary valve 130. The speed change gear 140 isrotatably fitted into a bottomed tubular space Hp2c recessed furthertoward a back side than the bottomed tubular space Hp2b recessed at acentral portion of the second pump housing Hp2 into which the rotaryvalve 130 is inserted.

The speed change gear 140 includes the sun gear 141, the four planetarygears 142, and an internal gear 143.

The sun gear 141 is formed with a cylindrical portion 141 a extending inthe direction of the rotational axis. Also, the rotary shaft 113 of theactuator 110 is integrally rotatably fitted to an inner periphery of thecylindrical portion 141 a via the driving power interrupting device 150for a valve.

The four planetary gears 142 are meshed with the sun gear 141 at equalangular intervals. Also, the protrusions 135 of the rotary valve 130 areinserted between the planetary gears 142 so that the rotary valve 130 isrotatable with the revolution of the planetary gears 142 around the sungear 141.

The internal gear 143 is integrally provided at an inner periphery ofthe space Hp2c of the second pump housing Hp2. The four planetary gears142 are meshed with the internal gear 143 at equal angular intervals. Inaddition, the internal gear 143 may be provided separately from thesecond pump housing Hp2 and may be pin-coupled to the second pumphousing Hp2.

The driving power interrupting device 150 for a valve is a one-wayclutch that is switchable between a state where clockwise rotationaldriving power, illustrated in the drawing, of the actuator 110 istransmitted to the rotary valve 130 and a state where counterclockwiserotational driving power is interrupted. The driving power interruptingdevice 151 for a pump is a one-way clutch that is switchable between astate where counterclockwise rotational driving power, illustrated inthe drawing, of the actuator 110 is transmitted to the rotary pump 120and a state where clockwise rotational driving power is interrupted.

Accordingly, the rotary pump 120 and the rotary valve 130 can bereliably switched and rotationally driven. Also, the fluid can bereliably supplied to a predetermined destination without simultaneouslyactuating the rotational driving of the rotary pump 120 and therotational driving of the rotary valve 130. In addition, it is alsopossible to use a frictional plate type clutch instead of the one-wayclutch.

As illustrated in FIG. 7, the phase detecting mechanism 160 isconstituted of the recesses 161 having a wedge-shaped radialcross-section, and the phase detecting sensor 162. The recesses 161 areprovided at intervals of 45 degrees in the valve outer periphery 130 eof the rotary valve 130. The phase detecting sensor 162 is a sensorusing an eddy current, magnetism, or the like, is provided so that asensor portion is fixed to a side surface of the second pump housing Hp2and a tip portion makes the amount of protrusion from an innerperipheral surface of the second pump housing Hp2 to a radial inner sidevariable by means of a spring 163.

Since a high pressure is applied to the rotary valve 130 during theoperation of the rotary pump 120, there is a concern that the rotaryvalve 130 may idle with only the driving power interrupting device 150for a valve. However, since the recesses 161 to be locked in thecircumferential direction to the phase detecting sensor 162 areprovided, the idling of the rotary valve 130 can be prevented.

As illustrated in FIG. 7, the check valve 180 is constituted of thevalve body 181 and the compression spring 182. The valve body 181 isalways pressed against the discharge port of the locking discharge flowpassage 138 by the spring force of the compression spring 182 during thestop of the rotary pump 120. Accordingly, a back flow of the hydraulicoil to the locking discharge flow passage 138 can be regulated.

Additionally, during the driving of the rotary pump 120, the valve body181 is separated from the discharge port of the locking discharge flowpassage 138 against the spring force of the compression spring 182 bythe hydraulic oil discharged from the locking discharge flow passage138. Accordingly, the supply of the hydraulic oil to the clutch device 7side is permissible.

As illustrated in FIG. 4, the accumulator 190 is a pressure accumulationdevice that is connected to the second flow passage P2, accumulates,when the pressure of hydraulic oil within the second flow passage P2 isequal to or higher than a predetermined pressure, the hydraulic oil, anddischarges the hydraulic oil accumulated in the second flow passage P2during the stop of the rotary pump 120 when the pressure of thehydraulic oil within the second flow passage P2 is reduced. Accordingly,the pressure of the fluid can be maintained for a prolonged period oftime. Hence, the driving of the rotary pump 120 can be stopped for along time, and the current consumption of the driving power transmissiondevice can be suppressed.

As illustrated in FIG. 4, the control device 200 has a function of,according to the normal mode, the locking mode, and the auxiliarytransmission switching mode, controlling the rotational driving of theactuator 110 on the basis of the phase of the rotary valve 130 detectedby the phase detecting mechanism 160 and controlling the rotationaldriving of the actuator 110 on the basis of the pressure of thehydraulic oil detected by the pressure detecting mechanism 170.Accordingly, the driving of the actuator can be exactly controlled sothat the destination of the fluid becomes accurate. Additionally, thedriving of the actuator can be exactly controlled so that the pressureof the fluid becomes proper.

(Operation of Pump Apparatus with Switching Valve)

Next, the respective operations of the normal mode, the locking mode,and the auxiliary transmission switching mode of the pump apparatus 100with a switching valve will be described with reference to the drawings.

In FIGS. 11A to 13B, a flowing direction of the hydraulic oil is shownas an arrow. In the normal mode, as illustrated in FIG. 11A, the opening131 d of the suction flow passage 131 of the rotary valve 130 coincideswith the opening 136 a of the communication suction flow passage 136,and the opening 131 b of the flow passage 131 c for drain coincides withthe opening 136 d of the flow passage 136 c for communication drain.Additionally, the opening 132 b of the discharge flow passage 132 of therotary valve 130 coincides with the opening 137 a of the normaldischarge flow passage 137.

If the rotary pump 120 is rotationally driven in this state, thehydraulic oil within the reserve tank T is sucked from the communicationsuction flow passage 136 through the suction flow passage 131 into thepump chamber 124. The hydraulic oil made to have a high pressure withinthe pump chamber 124 is discharged from the discharge flow passage 132through the normal discharge flow passage 137 to the flow control valve152.

Then, as illustrated in FIG. 11B, the flow control valve 152 is moved toa position where the drain port 136 e is closed, by a pressuredifference caused as the hydraulic oil passes through the throttle 152 aof the flow control valve 152. The hydraulic oil that has passed throughthe flow control valve 152 is supplied to the cylinder device 73 of theclutch device 7 through the first flow passage P1, and makes themultiple disc clutch 72 engaged with a predetermined pressure accordingto a pressure detection signal of the pressure detecting mechanism 170.Thereafter, the rotational driving of the rotary pump 120 is controlledaccording to the pressure detection signal of the pressure detectingmechanism 170 so that the multiple disc clutch 72 is engaged with apredetermined pressure.

If the rotational driving of the rotary pump 120 is stopped asillustrated in FIG. 11C, the pressure difference within the flow controlvalve 152 is eliminated. Thus, the flow control valve 152 is moved to aposition where the drain port 136 e is opened, by the restoring force ofthe compression spring 152 b. The hydraulic oil within the cylinderdevice 73 of the clutch device 7 is returned from the first flow passageP1 through the drain port 136 e and the flow passage 131 c for drain tothe reserve tank T. The normal mode is completed through the above.

In the locking mode, as illustrated in FIG. 12A, the opening 131 b ofthe flow passage 131 c for drain of the rotary valve 130 is closed bythe lid 130 f. Additionally, the opening 132 b of the discharge flowpassage 132 of the rotary valve 130 coincides with the opening 138 a ofthe locking discharge flow passage 138.

In this state, since the first flow passage P1 side, the normaldischarge flow passage 137, and the drain port 136 e side of the flowcontrol valve 152 are all closed, a state where the hydraulic pressurethat is present in the flow control valve 152 is equal to the hydraulicpressure of the cylinder device 73 of the clutch device 7 and thehydraulic pressure of the accumulator 190 is brought about.

If the rotary pump 120 is rotationally driven in this state, asillustrated in FIG. 12B, the hydraulic oil within the reserve tank T issucked from the communication suction flow passage 136 through thesuction flow passage 131 into the pump chamber 124. The hydraulic oilmade to have a high pressure within the pump chamber 124 opens the checkvalve 180 through the locking discharge flow passage 138 from thedischarge flow passage 132.

Then, the hydraulic oil that has passed through the check valve 180 issupplied to the cylinder device 73 of the clutch device 7 through thesecond flow passage P2, and makes the multiple disc clutch 72 engagedwith a predetermined pressure according to the pressure detection signalof the pressure detecting mechanism 170. If the multiple disc clutch 72is engaged with a predetermined pressure, the hydraulic oil that haspassed through the check valve 180 is supplied to the accumulator 190.If the pressure of the accumulator 190 reaches a predetermined pressureaccording to the pressure detection signal of the pressure detectingmechanism 170, the rotational driving of the rotary pump 120 is stopped.

If the supply of the hydraulic oil passing through the locking dischargeflow passage 138 from the discharge flow passage 132 is stopped asillustrated in FIG. 12C, the check valve 180 is closed by the restoringforce of the compression spring 182. Then, when the pressure of themultiple disc clutch 72 is lowered, the hydraulic oil is supplied fromthe accumulator 190, and the multiple disc clutch 72 is engaged with apredetermined pressure. Then, if the pressure of the accumulator 190 islowered, the rotary pump 120 is rotationally driven again, and theabove-described operation is repeated until the locking mode iscompleted.

In the auxiliary transmission switching mode (Hi), as illustrated inFIG. 13A, the opening 132 b of the discharge flow passage 132 of therotary valve 130 coincides with the opening 139 d of the second suctionand discharge flow passage 139 b, and the opening 131 b of the flowpassage 131 c for drain coincides with the opening 139 c of the firstsuction and discharge flow passage 139 a. Additionally, the opening 131d of the suction flow passage 131 of the rotary valve 130 is closed.

If the rotary pump 120 is rotationally driven in this state, thehydraulic oil within the region 41 a of the cylinder device 4 is suckedfrom the third flow passage P3 through the first suction and dischargeflow passage 139 a and the flow passage 131 c for drain into the pumpchamber 124. Then, the hydraulic oil within the pump chamber 124 issupplied from the discharge flow passage 132 through the second suctionand discharge flow passage 139 b and the fourth flow passage P4 to theregion 41 b of the cylinder device 4 of the auxiliary transmission 4,moves the piston 42 to the region 41 a side, and performs switching to aspeed change Hi. The auxiliary transmission switching mode (Hi) iscompleted through the above.

In the auxiliary transmission switching mode (Lo), as illustrated inFIG. 13B, the opening 132 b of the discharge flow passage 132 of therotary valve 130 coincides with the opening 139 c of the first suctionand discharge flow passage 139 a, and the opening 131 b of the flowpassage 131 c for drain coincides with the opening 139 d of the secondsuction and discharge flow passage 139 b. Additionally, the opening 131d of the suction flow passage 131 of the rotary valve 130 is closed.

If the rotary pump 120 is rotationally driven in this state, thehydraulic oil within the region 41 b of the cylinder device 4 is suckedfrom the fourth flow passage P4 through the second suction and dischargeflow passage 139 b and the flow passage 131 c for drain into the pumpchamber 124. Then, the hydraulic oil within the pump chamber 124 issupplied from the discharge flow passage 132 through the first suctionand discharge flow passage 139 a and the third flow passage P3 to theregion 41 a of the cylinder device 4 of the auxiliary transmission 4,moves the piston 42 to the region 41 b side, and performs switching to aspeed change Lo. The auxiliary transmission switching mode (Lo) iscompleted through the above.

According to the pump apparatus with a switching valve of the presentembodiment, the rotational driving of the rotary pump 120 and therotational driving of the rotary valve 130 can be performed by oneactuator 110 by performing switching using the driving powerinterrupting device 150 for a valve. Thus, the drive control of oneactuator 110 becomes simple, and the high-speed operation of the pumpapparatus 100 with a switching valve is possible. Additionally, sincethe number of devices can be reduced, remarkable cost reduction can beachieved.

According to the driving power transmission device of the presentembodiment, the normal mode and the locking mode are switched by therotary valve 130. Thus, the pressure of the fluid can be maintained evenif the driving of the rotary pump 120 is stopped in the locking mode.Accordingly, the current consumption of the driving power transmissiondevice can be suppressed.

According to the pump apparatus with a switching valve of the presentembodiment, the reduction ratio when the rotational driving power of theactuator 110 is transmitted to the rotary pump 120 is greater than thereduction ratio when the rotational driving power is transmitted to therotary valve 130. Thus, the rotational driving of the rotary pump 120and the rotary valve 130 can be performed, respectively, by one actuator110. Hence, the pump apparatus 100 with a switching valve can be simplycontrolled, and an improvement in pump efficiency and an improvement invalve positioning accuracy can be made compatible.

(Others)

In addition, in the above-described embodiment, the cam ring 121 of therotary pump 120 is separately provided. However, the shape of the camring 121 may be provided at the side plate 125. Accordingly, the leakingof oil between the rotary pump 120 and the rotary valve 130 can bereduced, and integral rotation of the side plate 125 and the rotaryvalve 130 can be more smoothly performed.

Additionally, in the above-described embodiment, the actuator 110, therotary pump 120, the rotary valve 130, and the speed change gear 140 areintegrated. However, a configuration may be adopted in which the rotarypump 120 is directly connected to the actuator 110, and the actuator 110and the rotary valve 130 are coupled together via a gear mechanism(speed change gear 140), a belt pulley mechanism, or the like.

Additionally, although the above-described embodiment provides aconfiguration in which the rotational phase of the rotary valve 130 isdetected by the phase detecting mechanism 160, a configuration may beadopted in which the actuator 110 includes a rotary encoder or therotational phase is detected using a stepping motor as the actuator 110.Additionally, although the pressure of the hydraulic oil within therotary valve 130 is detected by the pressure detecting mechanism 170, aconfiguration may be adopted in which the pressure of the hydraulic oilis detected by the driving current of the actuator 110.

Additionally, although the above-described embodiment provides aconfiguration in which the rotary valve 130 is rotated using a reductiongear as the speed change gear 140, a configuration may be adopted inwhich the rotary pump 120 is rotated using a speed increasing gear asthe speed change gear 140. Accordingly, since the speed change gear 140can be simply configured, cost reduction of the pump apparatus 100 witha switching valve can be achieved. Additionally, a configuration may beadopted in which the rotary pump 120 is rotated using a first reductiongear as the speed change gear 140 and the rotary valve 130 is rotatedusing a second reduction gear with a greater reduction ratio than thefirst reduction gear. Accordingly, the pumping pressure of the rotarypump 120 can be increased.

What is claimed is:
 1. A pump apparatus with a switching valve,comprising: an actuator that is rotationally driven; a pump thatdischarges a fluid sucked by rotational driving of the actuator; aswitching valve that is changed in phase by the rotational driving ofthe actuator so as to be switchable among a plurality of destinations ofthe fluid discharged from a pump chamber of the pump; and a drivingpower interrupting device for a valve that is switchable between a statewhere rotational driving power of the actuator is transmitted to theswitching valve and a state where the rotational driving power of theactuator is interrupted, wherein the pump is a rotary pump that makesthe pressure of the sucked fluid high through the rotational driving ofthe actuator to discharge the high-pressure fluid, and wherein the pumpapparatus with a switching valve further includes a speed change gearthat makes a reduction ratio when the rotational driving power of theactuator is transmitted to the rotary pump greater than a reductionratio when the rotational driving power of the actuator is transmittedto the switching valve.
 2. The pump apparatus with a switching valveaccording to claim 1, wherein the driving power interrupting device fora valve transmits the rotational driving power of the actuator in onerotational direction to the switching valve and interrupts therotational driving power of the actuator in the other rotationaldirection with respect to the switching valve.
 3. The pump apparatuswith a switching valve according to claim 2, wherein the driving powerinterrupting device for a valve is a one-way clutch that transmits therotational driving power of the actuator in the other rotationaldirection to the switching valve and interrupts the rotational drivingpower of the actuator in one rotational direction, and the pumpapparatus with a switching valve includes a driving power interruptingdevice for a pump that is a one-way clutch and transmits the rotationaldriving power of the actuator in one rotational direction to the pumpand interrupts the rotational driving power of the actuator in the otherrotational direction.
 4. The pump apparatus with a switching valveaccording to claim 2, further comprising: a phase detecting mechanismcapable of detecting and positioning the phase.
 5. The pump apparatuswith a switching valve according to claim 4, further comprising: acontrol device that controls rotational driving of the actuator on thebasis of the phase of the switching valve detected by the phasedetecting mechanism.
 6. The pump apparatus with a switching valveaccording to claim 4, wherein The phase detecting mechanism isconstituted of a sensor that is fixed to the housing that rotatablyhouses the rotary valve and is provided to make the amount of protrusionfrom an inner peripheral surface of the housing to a radial inner sidevariable, and a recess that that is formed in an outer peripheralsurface of the switching valve and is locked to the sensor in acircumferential direction.
 7. The pump apparatus with a switching valveaccording to claim 1, wherein the actuator rotationally drive the pumpwith the rotational driving power of the actuator in one rotationaldirection, and the driving power interrupting device for a valvetransmits the rotational driving power of the actuator in the otherrotational direction to the switching valve.
 8. The pump apparatus witha switching valve according to claim 1, further comprising: a housingthat rotatably houses the switching valve, wherein the switching valveincludes a braking device that is switchable between a state where therotation thereof with respect to the housing is constrained and a statewhere the rotation thereof with respect to the housing is released, thebraking device releases the switching valve when the actuator isrotationally driven in one rotational direction, and the braking deviceconstrains the switching valve when the actuator is rotationally drivenin the other rotational direction.
 9. The pump apparatus with aswitching valve according to claim 1, wherein a rotational axis of theactuator, a rotational axis of the pump, and a rotational axis of theswitching valve are coaxially provided, an end surface of the switchingvalve forms a side wall of a pump chamber of the pump, and the pumpapparatus with a switching valve includes a housing that houses the pumpand the switching valve.
 10. The pump apparatus with a switching valveaccording to claim 9, wherein at least one of the switching valve and asurface of the housing facing the switching valve is provided with acircumferential groove into which a fluid discharged from the pumpchamber is made to flow, and the housing is provided with acommunication hole that communicates a pressure detecting mechanism withthe circumferential groove.
 11. The pump apparatus with a switchingvalve according to claim 10, further comprising: a control device thatcontrols rotational driving of the actuator on the basis of the pressureof the fluid detected by the pressure detecting mechanism.
 12. The pumpapparatus with a switching valve according to claim 9, furthercomprising: a side plate that forms a side wall of the pump chamberopposite to the switching valve, wherein the pump includes an outerrotor and an inner rotor and includes a cam ring that eccentrically androtatably supports the outer rotor with respect to the inner rotor, andthe switching valve, the side plate, and the cam ring rotate integrally.13. The pump apparatus with a switching valve according to claim 12,wherein the side plate is housed in the housing, and a back-pressurechamber, into which the fluid discharged from the pump chamber flows,and applying a pressing force to the pump side to the side plate withthe pressure of the fluid, is provided between an end surface of theside plate opposite to the pump chamber in a direction of a rotationalaxis and the housing facing the end surface of the side plate in thedirection of the rotational axis.
 14. The pump apparatus with aswitching valve according to claim 12, further comprising: a thrustbearing arranged at the housing so as to sandwich the pump, theswitching valve, and the side plate in the direction of the rotationalaxis.
 15. The pump apparatus with a switching valve according to claim1, wherein the switching valve is changed in phase so as to beswitchable among a plurality of return points made to communicate with asuction side of the pump chamber of the pump.
 16. The pump apparatuswith a switching valve according to claim 1, wherein the speed changegear is a reduction gear coupled to the switching valve, and the rotarypump is directly connected to the actuator.
 17. The pump apparatus witha switching valve according to claim 1, wherein the speed change gearincludes a first reduction gear coupled to the switching valve and asecond reduction gear coupled to the rotary pump.
 18. The pump apparatuswith a switching valve according to claim 1, wherein a rotational axisof the actuator, a rotational axis of the rotary pump, a rotational axisof the switching valve, and a rotational axis of the speed change gearare coaxially provided, an end surface of the switching valve forms aside wall of the pump chamber, and the pump apparatus with a switchingvalve includes a housing that houses the rotary pump, the switchingvalve, and the speed change gear.
 19. The pump apparatus with aswitching valve according to claim 18, further comprising: a side platethat forms a side wall of the pump chamber opposite to the switchingvalve, wherein the rotary pump includes an outer rotor and an innerrotor and include a cam ring that eccentrically and rotatably supportsthe outer rotor with respect to the inner rotor, and the switchingvalve, the side plate, the cam ring, and the speed change gear rotateintegrally.
 20. The pump apparatus with a switching valve according toclaim 19, further comprising: a thrust bearing arranged at the housingso as to sandwich the rotary pump, the switching valve, the side plate,and the speed change gear in the direction of the rotational axis.